Code No.B1609
Seat belt pre-tensioner (passenger’s side) (squib) system
(short circuit between squib
circuit terminals)
caution |
If diagnosis code B1609 is
set in the SRS-ECU, be sure to diagnose the CAN bus
line.
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OPERATION
Only when the frontal impact exceeding the
threshold is simultaneously detected (turned
ON) by the front impact sensor as well as by the analogue G-sensor and
safing G-sensor in SRS-ECU,
the electric current is supplied from SRS-ECU to the seat belt
pre-tensioner (squib).
TROUBLE JUDGEMENT
The code is set when the short circuit
occurs to between the terminals of SRS-ECU seat
belt pre-tensioner (passenger’s side) (squib) circuit.
PROBABLE CAUSES
- Damaged short spring *
- Short circuit between terminals of seat belt pre-tensioner
(passenger’s
side) (squib) circuit
- Damaged connector(s)
- Malfunction of SRS-ECU
- Insufficient press of locking button or locking button not
pressed
note |
*: The squib circuit connectors
integrate a short spring (which prevents the
seat belt pre-tensioner from being unintentionally deployed
because of static electricity by
shorting the positive wire to the earth wire in the squib
circuit when the connectors are disconnected).
Therefore, when the above codes are set, the short spring
may not be released due to the damaged
connector even when the connectors are connected.
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STEP 1. M.U.T.-III CAN bus diagnostics.
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Use M.U.T.-III to diagnose the CAN
bus lines.
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Q.
Is the check result normal?
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Go to Step
2.
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Repair the CAN bus
line (Refer to GROUP 54C - Troubleshooting ).
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STEP 2. Check whether the diagnosis code is set
again.
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(1)Connect the negative battery terminal.
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(2)After erasing the diagnosis code memory, check
the diagnosis code again.
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(3)Disconnect the negative battery
terminal.
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Q.
Is diagnosis code No. B1609 set?
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Go to Step
3.
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Intermittent
malfunction (Refer to GROUP 00 - How to Use
Troubleshooting/Inspection
Service Points - How to Cope with Intermittent
Malfunction ).
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STEP 3. Connector check: SRS-ECU, seat belt
pre-tensioner (passenger’s
side).
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(1)Check that the negative battery terminal is
disconnected. If the negative battery
terminal is connected, disconnect it.
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(2)Disconnecting the SRS-ECU connector, connect it
again.
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![](../../../img/52/ACE02069AC00ENG.png)
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(3) After disconnecting the seat
belt pre-tensioner (passenger’s side) harness side
connector, connect the connector again. For the seat belt
pre-tensioner (passenger’s
side) harness side connector disconnection, use the
flat-tipped screwdriver to pull out the
harness side connector locking button. After releasing the
lock, disconnect the harness side connector. (4)Connect
the negative battery terminal. (5)After erasing the
diagnosis code memory, check the diagnosis code
again. (6)Disconnect the negative battery
terminal.
Q.
Is diagnosis code No. B1609 set?
Go to Step
4.
Replace
the connector concerned.
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STEP 4. Diagnosis check by dummy resistor
connection.
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(1)Check that the negative battery terminal is
disconnected. If the negative battery
terminal is connected, disconnect it.
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![](../../../img/52/ACE02069AC00ENG.png)
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(2)Use the flat-tipped screwdriver
to pull out the locking button of harness side connector.
After releasing the lock, disconnect the seat belt
pre-tensioner (passenger’s side) harness
side connector.
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![](../../../img/52/AC301553DP00ENG.png)
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(3)Connect special tool dummy
resistor (MB991865) to special tool resistor harness
(MB991884). (4)Connect special tool resistor harness to
the seat belt pre-tensioner (passenger’s
side) harness side connector. (5)Connect the negative
battery terminal. (6)After erasing the diagnosis code
memory, check the diagnosis code again. (7)Disconnect the
negative battery terminal.
Q.
Is diagnosis code No. B1609 set?
Go to Step
5.
Replace
the seat belt with pre-tensioner (passenger’s side)
(Refer to ).
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STEP 5. Resistance measurement at the SRS-ECU
connector.
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(1)Check that the negative battery terminal is
disconnected. If the negative battery
terminal is connected, disconnect it.
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(2)Disconnect the SRS-ECU connector.
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![](../../../img/52/ACE02069AC00ENG.png)
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(3)
danger |
To release the SRS-ECU
connector short spring in the
following operations, disconnect this seat belt
pre-tensioner connector, and keep the squib
circuit shorted.
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Use the flat-tipped screwdriver to pull out the
locking button of harness side connector.
After releasing the lock, disconnect the seat belt
pre-tensioner (passenger’s side)
harness side connector.
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![](../../../img/52/ACE02056AB00ENG.png)
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(4)
caution |
The short spring may not be
released due to the insufficient insertion.
Therefore, insert
the insulator for 4 mm or more.
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Insert an insulator (width: 3 mm, thickness: 0.5 mm)
such as cable tie between the PTA+,
PTA- line and the short spring, and release the short
spring. (5)Take the measurements below at the SRS-ECU
harness side connector.
- Continuity between PTA+, PTA- line
OK: No continuity
Q.
Is the check result normal?
Go to Step
6.
Repair
the wiring harness PTA+, PTA- line between the SRS-ECU
connector
and the seat belt pre-tensioner (passenger’s side)
connector.
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STEP 6. Check whether the diagnosis code is set
again.
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Q.
Is diagnosis code No. B1609 set?
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Replace SRS-ECU
(Refer to ).
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Intermittent
malfunction (Refer to GROUP 00 - How to Use
Troubleshooting/Inspection
Service Points - How to Cope with Intermittent
Malfunction ).
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